On 2013-03-21 02:59, Luca Beltrame wrote:
This occurs with the latest 2.3. Example case:
robjects.IntVector([0,1,2]) + 1
This is what it returns
<IntVector - Python:0x7fadd7a7a320 / R:0xb385b18>
[ 0, 1, 2, 1]
While I'd expect, like in R
c(0,1,2) + 1
[1] 1 2 3
Is this a bug, or do I have to do things differently?
The idea was that a vector would behave like a Python sequence. For example
>>> x = [1,2]
>>> x + [3, ]
[1,2,3]
Now where I met ambiguity bridging the two worlds (Python and R) is that
there is no such thing as a scalar in R (they are vectors of length 1).
In Python this is an error.
>>> x+3
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: can only concatenate list (not "int") to list
Since I am converting Python scalars into vectors whenever passing them
to R I must have thought that this should be the same for when
__add__ is used. Now I see that in the current robjects model,
`robjects.IntVector([0,1,2]) + 1` should raise a type Error.
To use R-style operation, I solved this by adding a delegating attribute
called `ro` (R operator).
For example here:
robjects.IntVector([0,1,2]).ro + 1
(documentation is here:
http://rpy.sourceforge.net/rpy2/doc-2.3/html/vector.html#operators
).
L.
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